Effect of uniform heating rate on the nature of thermoluminescence of glass

1963 ◽  
Vol 20 (9) ◽  
pp. 476-477
Author(s):  
R. V. Lipchanskaya ◽  
V. S. Aksenov
Keyword(s):  
Heating Rate ◽  
Uniform Heating

Assessment of Heating Rate and Non-uniform Heating in Domestic Microwave Ovens

2012 ◽  
Vol 46 (4) ◽  
pp. 229-240 ◽  
Author(s):  
Krishnamoorthy Pitchai ◽  
Sohan L. Birla ◽  
David Jones ◽  
Jeyamkondan Subbiah
Keyword(s):  
Heating Rate ◽  
Uniform Heating

scholarly journals A flowline model for Nigardsbreen, Norway: projection of future glacier length based on dynamic calibration with the historic record

1997 ◽  
Vol 24 ◽  
pp. 382-389 ◽  
Author(s):  
J. Oerlemans
Keyword(s):  
Mass Balance ◽  
Heating Rate ◽  
Computer Model ◽  
Flow Model ◽  
Perfect Match ◽  
Greenhouse Warming ◽  
Dynamic Calibration ◽  
Uniform Heating ◽  
Glacier Length ◽  
Historic Record

Historic glacier-length variations are used to constrain a computer model for Nigardsbreen, Norway. A mass-balance history is derived that, when imposed on the flow model, gives an almost perfect match between observed and simulated glacier length since AD 1748. Being calibrated with past changes, the model predicts an 800 m advance of the glacier snout if mass-balance conditions remain as they were for the period 1962–93. Several greenhouse-warming scenarios are imposed to project the glacier’s behaviour into the next century. For a uniform heating rate of 0.02 K a–1, Nigardsbreen would advance slightly until AD 2020, but then a very rapid retreat would start: in AD 2100 glacier volume would be only 10% of the 1950 volume.

THE DIFFERENTIAL THERMAL ANALYSIS OF NATURAL AND SYNTHETIC HYDRATES OF CALCIUM SULPHATE

1960 ◽  
Vol 38 (6) ◽  
pp. 936-943 ◽  
Author(s):  
W. E. P. Fleck ◽  
M. H. Jones ◽  
R. A. Kuntze ◽  
H. G. McAdie
Keyword(s):  
Heating Rate ◽  
Calcium Sulphate ◽  
Endothermic Effect ◽  
Exothermic Effect ◽  
Uniform Heating ◽  
Heating Rates ◽  
Sample Concentration ◽  
Naturally Occurring ◽  
Lower Temperature ◽  
Dehydration Behavior

A variety of naturally occurring forms of calcium sulphate dihydrate produce substantially identical differential thermograms under conditions of uniform heating rate and particle size. These thermograms closely resemble those for synthetic dihydrate and β-hemihydrate, showing four endothermic effects and one exothermic effect below 500 °C. Two of these endothermic effects, at about 170° and 300 °C, respectively, which have not been reported previously, were found to be easily masked by changes in heating rate or sample concentration. Resolution of the several effects was improved by using different heating rates at different stages of the thermogram. Thermograms of the α-hemihydrate were similar, except that the endothermic effect at 300 °C was not evident and the exothermic effect occurred at a much lower temperature than for the dihydrate. No conspicuous differences were found in the temperatures corresponding to the various endothermic and exothermic effects which might be correlated with the general dehydration behavior of the particular material. The endothermic effect at about 170 °C appears to be associated with part of the hemihydrate to soluble anhydrite transition, possibly arising during the removal of the last traces of water.

Microcalorimetry and Kinetics of Biodiesel

2014 ◽  
Vol 592-594 ◽  
pp. 1647-1651
Author(s):  
S.P. Sivapirakasham ◽  
A. Afsal Khan ◽  
Mane G. Yogesh ◽  
R. Anand
Keyword(s):  
Activation Energy ◽  
Kinetic Model ◽  
Heating Rate ◽  
Diesel Fuel ◽  
Fossil Fuel ◽  
Uniform Heating ◽  
Nitrogen Gas ◽  
Gas Atmosphere ◽  
Great Acceptance ◽  
Kinetics Of

Now a day biodiesel becomes best alternative for diesel fuel. Thermogravimetry technique has great acceptance in the field of fossil fuel. The thermal and kinetics properties of diesel and Jatropha biodiesel are analyzed by using popular technique of thermogravimetry. The aim is to study the behavior of diesel, biodiesel and their blends in Nitrogen gas atmosphere at the heating rate of 5K/min, 10K/min and 15K/min from 30°C to 600°C. From study it is found that as heating rate increases peak is shifting toward higher value which shows that there is less uniform heating. The study clearly shows biodiesel is more stable than diesel indicating that transesterification make sample less stable. The Arrehenius Kinetic model is applied to study the activation energy. As percentage of biodiesel increases, stability of sample increases and hence increases in activation energy

Alternative Cavity Design for Microwave Joining of Long Ceramic Tubes

1994 ◽  
Vol 347 ◽  
Author(s):  
Hussamaldin S. Sa'adaldin ◽  
W. Murray Black ◽  
Iftikhar Ahmad ◽  
Yong-Lai Tian ◽  
Richard Silberglitt
Keyword(s):  
Heating Rate ◽  
Single Mode ◽  
Preliminary Test ◽  
Rectangular Cavity ◽  
Test Results ◽  
Uniform Heating ◽  
Ceramic Samples ◽  
Cavity Design

ABSTRACTA new single mode applicator has been designed and fabricated to provide effective and nearly uniform heating of long ceramic tubes or rods at 2.45 GHz. The applicator is made of two double mitered waveguide corners. A comparison between the new cavity and a rectangular cavity has been carried out to heat various ceramic samples. Results show a significant improvement in the heating rate as well as the reduction of the power needed to attain a given temperature. This paper describes the preliminary test results of the new cavity and the potential to achieve joining of long tubes or rods.

Analysis of Microwave Heating for Composite Dielectric Food Substances Supported on Ceramic Materials

2005 ◽  
Author(s):  
Tanmay Basak ◽  
A. Meenakshi
Keyword(s):  
Heating Rate ◽  
Thermal Processing ◽  
Preliminary Analysis ◽  
Average Power ◽  
Ceramic Materials ◽  
Uniform Heating ◽  
Small Thickness ◽  
Resonance Modes ◽  
Time Plot ◽  
Oil Thickness

A detailed theoretical analysis has been carried out to study efficient heating of 1D composite dielectric samples due to microwaves. Current study involves processing of beef with oil layers with/without support and three cases are considered where oil layer is followed by beef layer (case 1), beef layer is followed by oil layer (case 2) and oil-beef layers are exposed to microwaves at both the sides (case 3). For cases 1 and 2, microwaves are incident at the left face only and the support is generally attached with the oil layer. A preliminary analysis has been carried out for beef-oil composite without any support for all cases and it is observed that identical average power in beef sample occurs for small thickness of oil layer irrespective of either oil or beef directly exposed to microwaves (case 1 or 2) and for greater thicknesses of oil layer, the food composite would exhibit greater average power for case 1. The maxima in average power corresponding to resonances occur at various sample thicknesses for all cases with and without supports and two dominant resonance modes R1 and R2 are considered where the average power at R1 mode is greater than that at R2 mode for all cases. The detailed spatial distribution for various cases illustrates that for small oil thicknesses, heating rate is less and greater heating rate would correspond to larger oil thicknesses. However, the excessive heating in beef sample may correspond to thermal runaway which are also illustrated by ΔTb (difference between the maximum and minimum values of temperature) in beef samples vs time plot. The similar analysis has been extended for all cases with oil layer directly attached with ceramic supports (Al2O3 and SiC). Based on the detailed analysis, the suitability of the support would be guided by factors such as optimal oil thickness, uniform heating and enhanced thermal processing within the beef sample.

scholarly journals A flowline model for Nigardsbreen, Norway: projection of future glacier length based on dynamic calibration with the historic record

1997 ◽  
Vol 24 ◽  
pp. 382-389 ◽  
Author(s):  
J. Oerlemans
Keyword(s):  
Mass Balance ◽  
Heating Rate ◽  
Computer Model ◽  
Flow Model ◽  
Perfect Match ◽  
Greenhouse Warming ◽  
Dynamic Calibration ◽  
Uniform Heating ◽  
Glacier Length ◽  
Historic Record

Historic glacier-length variations are used to constrain a computer model for Nigardsbreen, Norway. A mass-balance history is derived that, when imposed on the flow model, gives an almost perfect match between observed and simulated glacier length since AD 1748. Being calibrated with past changes, the model predicts an 800 m advance of the glacier snout if mass-balance conditions remain as they were for the period 1962–93. Several greenhouse-warming scenarios are imposed to project the glacier’s behaviour into the next century. For a uniform heating rate of 0.02 K a–1, Nigardsbreen would advance slightly until AD 2020, but then a very rapid retreat would start: in AD 2100 glacier volume would be only 10% of the 1950 volume.

A TEM study of the influence of microstructure on the superplastic behavior of a U-5.8 wt.% Nb alloy

1986 ◽  
Vol 44 ◽  
pp. 568-569
Author(s):  
G. Mackiewicz Ludtka
Keyword(s):  
Grain Size ◽  
Heating Rate ◽  
Phase Field ◽  
Single Phase ◽  
Superplastic Behavior ◽  
Two Phase ◽  
Single Phase Field

Historically, metals exhibit superplasticity only while forming in a two-phase field because a two-phase microstructure helps ensure a fine, stable grain size. In the U-5.8 Nb alloy, superplastici ty exists for up to 2 h in the single phase field (γ1) at 670°C. This is above the equilibrium monotectoid temperature of 647°C. Utilizing dilatometry, the superplastic (SP) U-5.8 Nb alloy requires superheating to 658°C to initiate the α+γ2 → γ1 transformation at a heating rate of 1.5°C/s. Hence, the U-5.8 Nb alloy exhibits an anomolous superplastic behavior.

Optimization of the time the chromatograph thermostats exit to a given temperature

2020 ◽  
pp. 40-45
Author(s):  
Nadezhda O. Vzduleva ◽  
Valery B. Gitlin
Keyword(s):  
Heating Rate ◽  
Entire Range ◽  
Gas Chromatograph ◽  
Heating And Cooling ◽  
Operating Temperatures ◽  
The Stability

The problems of ensuring the stability of the temperature of the chromatographic experiment carried out using a serial gas chromatograph LGH-3000 are considered. Limiting the permissible heating rate of the chromatograph thermostats does not allow a quick transition to the new conditions of the chromatographic experiment in accordance with the requirements of the technical conditions. The processes of heating and cooling the thermostat are analyzed. It is shown that the ratio of the duration of the interval equal to the sum of the durations of the heating and cooling intervals to the duration of the heating interval is inversely proportional to the temperature of the chromatographic experiment. Based on this situation, an empirical algorithm is proposed for heating the thermostat to a given temperature, which made it possible to reduce the time it takes to reach a given temperature in the entire range of operating temperatures.

Sign in / Sign up

Export Citation Format

Share Document